xdmod-update-resource-specs: fix resources file name

[kcgthb]

Description

The resource file name referenced in xdmod-update-resource-specs does not match the real file name.
The script references a resource-specs.json while the actual file name is resource_specs.json (underscore _ vs. dash -).

Motivation and Context

Running the current script results in the following error

# xdmod-update-resource-specs -r cluster --node-count 1000 --cpu-count 20000
PHP Warning:  file_get_contents(/etc/xdmod/resource-specs.json): failed to open stream: No such file or directory in /usr/share/xdmod/classes/CCR/Json.php on line 26
2019-10-02 09:33:17 [critical] Failed to read file '/etc/xdmod/resource-specs.json' (stacktrace: #0 /usr/bin/xdmod-update-resource-specs(168): CCR\Json::loadFile('/etc/xdmod/reso...')
#1 /usr/bin/xdmod-update-resource-specs(18): main()
#2 {main})

Tests performed

With the change, the script doesn't fail and the resource file is updated correctly.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project as found in the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[smgallo]

LGTM. Thanks for catching this.